Disadvantages of Page Flows

[salils]

Hello Friends,
I am using page flows for the first time. I would also need to run the web application under another j2ee server. I know that we can use the portability kit to do this transformation.Even though I understand that using page flows have certain advantages, I wanted to know whether there are disadvantages to using it too?

Some specific questions I had was:
1. Does using page flows slow down the web application?
2. Does using page flows increase the web app size?
3. Does it make it difficult to maintain?
4. Does using the portability kit have some disadvantages?

Thanks,
Salil